When the reIndex command is run the result document has two "ok" elements. Here's the output when run from the mongo shell:

> db.test.reIndex()
{
"nIndexesWas" : 2,
"msg" : "indexes dropped for collection",
"ok" : 1,
"nIndexes" : 2,
"indexes" : [
{
"name" : "id",
"ns" : "test.test",
"key" :

{ "_id" : 1 }

,
"v" : 0
},
{
"_id" : ObjectId("4d82279930d845dde2ea8fd1"),
"ns" : "test.test",
"key" :

{ "x" : 1 }

,
"name" : "x_1",
"v" : 0
}
],
"ok" : 1
}
>